Publication 89

Area selection for diamond exploration using deep-probing electromagnetic surveying

A.G. Jones and J.A. Craven

Abstract

Previously proposed methods of area selection for diamond-prospective regions have predominantly relied on till geochemistry, airborne geophysics, and/or an appraisal of tectonic setting. Herein we suggest that a novel deep-probing geophysical technique - electromagnetic studies using the natural-source magnetotelluric (MT) method - can contribute to such an activity. Essentially, diamondiferous regions must have (1) old lithosphere, (2) thick lithosphere, and (3) lithosphere that contains high concentrations of carbon. Deep-probing MT studies are able to address all three of these. The second and the third of these can be done virtually independently by MT, but for the first the geometries produced from modelling the MT observations must be interpreted with appropriate interaction with geologists, geochemists and other geophysicists. Examples are given from the Slave and Superior cratons in North America, with speculations about possible diamondiferous regions.

Source

Lithos, 77, 765-782.

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Alan G Jones / 16 September 2004 / alan-at-cp.dias.ie